Before providing specific background information in regard to the specific invention disclosed below, a brief general background is provided along with a few definitions for terms relevant to the discussion below.
In particular, 802.11 refers to a family of standards developed by the Institute of Electrical & Electronic Engineers (IEEE) for wireless Local Area Network (LAN) technology. The 802.11 standards specify an over-the-air interface between a wireless client and a base station or between two wireless clients.
There are several specifications in the 802.11 family. For example, basic 802.11 applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz frequency band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
802.11a is an extension to 802.11 that also applies to wireless LANs and provides up to 54 Mbps in the 5 GHz frequency band. 802.11a uses an orthogonal frequency division multiplexing (OFDM) encoding scheme rather than FHSS or DSSS.
802.11b, also referred to as 802.11 High Rate or Wi-Fi, is an extension to 802.11 that applies to wireless LANs and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the 2.4 GHz frequency band. 802.11b uses only DSSS.
802.11 g also applies to wireless LANs and provides 20+ Mbps transmission in the 2.4 GHz frequency band.
Communication systems designed around the 802.11 standards typically utilize amplifier devices for amplifying the RF signals. Due to restrictions mandated by the Federal Communications Commission (FCC) in the United States, the output power of most transmitters must be amplified before the Radio Frequency (RF) signal is transmitted via an antenna over the air. Several amplifier devices have been proposed for this purpose. However, conventional amplifiers typically comprise large bulky enclosures with big metal fins used for dissipating heat generated by the amplifier circuits. If the heat generated by the amplifier circuit is not dissipated properly by the casing of the amplifier circuit, the temperature will rise so high that some, if not all, of the electrical components comprising the amplifier will burn out and become inoperable. Further, high temperatures within the amplifier increase the collector charge and current gain of the RF components. High collector charge and current gain will decrease the performance of these components and force the equipment to malfunction. To address this issue, RF designers have conventionally used heavy bonded fins to dissipate the heat out of the amplifiers. This type of heatsink limits the mobility of the amplifier and, hence, the applications in which it can be used.
Additionally, conventional amplifiers are large and bulky and often do not provide provisions against lightning strikes. Since oftentimes this type of amplifier is located outdoors, it is often the case where the metal used to house the amplifier, or the cables leading to and from the amplifier, will attract lightning. If lightning strikes the amplifier, either directly or indirectly, and the device does not have provisions for dissipating the electricity, the results are typically fatal for the amplifier and, potentially, other equipment downstream from the amplifier. It has been suggested to provide lighting arrestors installed between the amplifier and the antenna. The addition of the lightning arresting device separate from the amplifier not only increases the overall expense, but it also increases the installation time necessary to install the system.